Image processing device

ABSTRACT

Signal processing including decoding and format conversion is executed on compressed image data at a high speed by simple control. 
     A decoder decodes compressed image data in units of blocks and writes the decoded data in the blocks into a decoded data memory. A progress notification unit generates a progress signal indicating a state of progress that data is being decoded or written into the decoded data memory by the decoder and outputs the signal to a format conversion unit per picture. The format conversion unit reads out the decoded data from the decoded data memory and format-converts the data, and writes the format-converted data into a format-converted data memory. In reading out data from the decoded data memory, the format conversion unit acquires information indicating an address of decoded data readable from the decoded data memory from the progress signal.

CROSS-REFERENCE TO RELATED APPLICATIONS

The disclosure of Japanese Patent Application No. 2013-025666 filed onFeb. 13, 1013 including the specification, drawings and abstract isincorporated herein by reference in its entirety.

BACKGROUND

The present invention relates to image processing and relates to atechnology for, for example, decoding compressed image data andperforming format-conversion on the decoded data.

Still images and moving images are both configured to bestored/transmitted in compressed states for capacity saving of a mediumfor storing images and improvement in image transmission speed. In thepresent specification, when just a word “image” is used, it includesboth of the still image and the moving image. In addition, the “image”and “image data” which is data indicating the image are used in the samemeaning unless otherwise specifically described.

A device (hereinafter, referred to as an “image utilization device”) onthe side that a compressed image is utilized includes a decoder meetingthe compression standards (JPEG, MPEG and so forth) of the image anddecodes the image by the decoder.

There are cases when an output format of the decoder and a format(hereinafter, referred to as a “utilization format”) that the imageutilization device uses for display are different from each other. Forexample, 3planar is known as an example of an image format(corresponding to the “utilization format”) that Android (a registeredtrademark) which is OS which is frequently adopted in a smartphone whichis one of the image utilization device is allowed to handle as systemrequirements. On the other hand, 2planar is generally known as anexample of the output format of the decoder.

Therefore, it is required to convert the format of image data (decodeddata) which has been output from the decoder to the utilization formatin the image utilization device.

Technologies which have been made from various viewpoints are proposedfor the image utilization device for which both of decoding of thecompressed data and format-conversion of the decoded image data arerequired.

For example, in Japanese Unexamined Patent Publication No. Hei 11(1999)-275575, there is disclosed a technique for allowing an MPEGdecoding device that both of an MPEG decoder for decoding an MPEG imageand a format conversion unit for undertaking format-conversion ofdecoded image data are built in to carry out the format-conversion inboth of the exterior and the interior of the MPEG decoding device. TheMPEG decoding device to which the above-mentioned technique is appliedincludes a selector for selectively outputting an output of the MPEGdecoder and an output of the format conversion unit. If an externalframe memory is coupled to the format conversion unit and the selectorprefers to select the output of the format conversion unit, the MPEGencoding device will be allowed to perform processing up toformat-conversion. On the other hand, if the selector prefers to selectthe output of the MPEG decoder and another format conversion unit isinstalled on the outside of the MPEG decoding device, the MPEG decodingdevice will be allowed to operate simply as the decoder.

In addition, in Japanese Unexamined Patent Publication No. 2003-169326,there is disclosed a technology that prior to decoding of encoded data(an compressed image), a picture is divided into a plurality of regionsper picture and decoding and format-conversion are sequentially andalternately executed again and again in units of divided regions inorder to save the capacity of the memory required for decoding andformat-conversion. According to this technology, it is allowed to savethe memory capacity in comparison with a case that the whole data, thatis, one-picture data (data corresponding to one picture) is stored.

Further, in Japanese Unexamined Patent Publication No. Hei 8(1996)-172602, there is disclosed a technology that in displaying acompressed image, the compressed data is decoded and written into amemory, the decoded data which has been written into the memory is readout by an FIFO in accordance with an output format and is temporarilystored. In this technology, writing of the data from the decoder to thememory is performed in units of blocks and reading of the data from thememory is performed in units of lines by laser scanning for the purposeof capacity saving of the memory for storing the decoded data similarlyto the technology described in Japanese Unexamined Patent PublicationNo. 2003-169326.

The technology disclosed in Japanese Unexamined Patent Publication No.Hei 11 (1999)-275575 is configured such that the decoded data is outputfrom the MPEG decoder directly to the format conversion unit both in acase where the data is format-converted by the format conversion unitbuilt into the MPEG decoding device and in a case where the data isformat-converted by the format conversion unit installed on the outsideof the MPEG decoding device (see FIGS. 1 to 3 in Japanese UnexaminedPatent Publication No. Hei 11 (1999)-275575).

Therefore, there is such a disadvantage that, for example, whenprocessing of format-conversion is delayed, it becomes difficult for theMPEG decoder to transfer the decoded data to the format conversion unitand execution of decoding and/or processing of the entire system delays.This disadvantage will cause to give a user an unpleasant filling, inparticular, in case of an image utilization device such as video chat, awireless display or the like that a reduction in time taken until thecompressed data is displayed after it has been input into the decoder isdesired.

In the technology disclosed in Japanese Unexamined Patent PublicationNo. 2003-169326, although it is allowed to perform a process of dividingthe picture concerned prior to decoding on a still image of JPEG systemor the like in many cases, it is difficult to perform theabove-mentioned process on a moving image in many cases. In addition,there is also such a disadvantage that control of picture division anddivided-region-based decoding/format-conversion is complicated and aload is imposed on the CPU.

The technology disclosed in Japanese Unexamined Patent Publication No.Hei 8 (1996)-172602 inevitably uses a memory controller (correspondingto a “synchronizing signal generator” in the embodiment of JapaneseUnexamined Patent Publication No. Hei 8 (1996)-172602) that generatestimings at which addresses in the memory are controlled, the data iswritten into the memory and the data is read out from the memory. Asillustrated in FIG. 3 or the like in Japanese Unexamined PatentPublication No. Hei 8 (1996)-172602, since this synchronizing signalgenerator generates the timings of data writing, data reading and soforth on the basis of a timing (a horizontal synchronizing signal, avertical synchronizing signal and so forth) upon data display, controlis complicated and the decoder may be kept waiting for the convenienceof display. As a result, such a disadvantage occurs that execution ofdecoding and/or processing of the entire system is delayed.

Other subject matters and novel features of the present invention willbecome apparent from the description of the present specification andappended drawings.

SUMMARY

According to one embodiment of the present invention, an imageprocessing device includes a decoded data memory, a format-converteddata memory, a decoder, a progress notification unit, and a formatconversion unit.

The decoded data memory is adapted to store decoded data obtained bydecoding compressed image data, and the format-converted data memory isadapted to store format-converted data obtained by performingformat-conversion on the decoded data.

The decoder decodes the compressed image data in units of blocks andwrites the decoded data in the blocks into the decoded data memory.

The progress notification unit generates and outputs a progress signalindicating a state of progress that data is being decoded by the decoderor a state of progress that the data is being written into the decodeddata memory by the decoder per picture.

The format conversion unit reads out the decoded data from the decodeddata memory and performs format-conversion on the data, and writes theformat-converted data into the format-converted data memory. The formatconversion unit acquires information indicating an address of decodeddata which is readable from the decoded data memory from the progresssignal from the progress notification unit.

Incidentally, those that the image processing device of theabove-mentioned embodiment is expressed by replacing it with a methodand a system, an image utilization device such as an image displaydevice or the like including the image processing device and so forthare effective as aspects of the present invention.

According to the above-mentioned one embodiment of the presentinvention, high-speed execution of image processing including decodingand format-conversion is allowed by simple control.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of an image processingdevice according to a first embodiment of the present invention;

FIG. 2 is a diagram illustrating examples of format-conversion that theimage processing device illustrated in FIG. 1 performs;

FIG. 3 is a diagram (1) illustrating an example of data decoding andwriting into a decoded data memory performed by a decoder in the imageprocessing device illustrated in FIG. 1;

FIG. 4 is a diagram (1) illustrating an example of data reading from thedecoded data memory by a format conversion unit in the image processingdevice illustrated in FIG. 1;

FIG. 5 is a diagram (2) illustrating an example of data decoding andwriting into the decoded data memory by the decoder in the dataprocessing device illustrated in FIG. 1;

FIG. 6 is a diagram illustrating an example of data reading from thedecoded data memory by the format conversion unit in the imageprocessing device illustrated in FIG. 1; and

FIG. 7 is a diagram illustrating an example of an image processingdevice according to a second embodiment of the present invention.

DETAILED DESCRIPTION

For clarification of explanation, the following description and drawingsare appropriately omitted and simplified. In addition, in the respectivedrawings, the same numerals are assigned to the same elements andduplicate description is omitted as required.

First Embodiment

FIG. 1 illustrates an example of an image processing device 100according to a first embodiment of the present invention. The imageprocessing device 100 includes a pre-stage processing unit 110, adecoded data memory 120, a format-converted data memory 130, and apost-stage processing unit 140 and a bitstream S0 which is compressedimage data is input into the device 100. Incidentally, in FIG. 1, a CPU(Central Processing Unit) which is generally included in the device ofthis type is omitted.

The pre-stage processing unit 110 performs decoding of the bitstream S0and format-conversion of decoded data. The post-stage processing unit140 performs processing such as displaying on format-converted dataobtained from the pre-stage processing unit 110, or the decoded data andthe format-converted data obtained from the pre-stage processing unit110. Since there are cases when the post-stage processing unit uses thedecoded data which is not yet format-converted in addition to theformat-converted data depending on the application of the imageprocessing device 100, also a signal line along which data (the decodeddata) is output from the decoded data memory 120 to the post-stageprocessing unit 140 is illustrated in FIG. 1. It goes without sayingthat in a case where the post-stage processing unit 140 does not use thedecoded data, this signal line is not installed.

The pre-stage processing unit 110 includes a decoder 112, a progressnotification unit 114, a format conversion unit 116, and a DMAC (DirectMemory Access Controller) 118.

The DMAC 118 sequentially transfers the bitstream S0 to the decoder 112in accordance with control by the not illustrated CPU.

The decoder 112 decodes the bitstream S0 which has been transferred fromthe DMAC 118 in units of blocks to obtain decoded data S1, and thenwrites the decoded data S1 into the decoded data memory 120 via the DMAC118.

The progress notification unit 114 generates a progress signal PRindicating a state of progress that the data is being decoded by thedecoder 112, or a state of progress the data is being written into thedecoded data memory 120 by the decoder 112 and outputs the progresssignal PR to the format conversion unit 116 per picture.

The progress signal PR is adapted to notify the format conversion unit116 of an address that decoded data which is readable from the decodeddata memory 120 is stored.

The decoder 112 performs decoding and writing of data in units ofblocks. The decoder 112 receives a notification that writing of thedecoded data in a certain block into the decoded data memory 1 q 20 hasbeen completed via the DMAC 118 and thereafter notifies the progressnotification unit 114 of completion of writing of the decoded data inthe above-mentioned block. Thus, the format conversion unit 116 isallowed to know completion (that is, the data becomes readable) ofwriting of the decoded data in the block concerned into the decoded datamemory 120 by receiving the progress signal PR.

In a case where the decoder 112 notifies the progress notification unit114 of a decoding time of the data in the block concerned as a decodingcompletion timing without waiting notification of completion of writingof the decoded data in a certain block into the decoded data memory 120,when there is a sufficient time difference until the format conversionunit 116 receives the progress signal PR after the progress signal PRhas been generated in accordance with completion of decoding ofone-block data by the decoder 112, the format conversion unit 116 isallowed to perceive that writing of the decoded data in the blockconcerned into the decoded data memory 120 has been completed byreceiving the progress signal PR.

It goes without saying that a difference between a time at whichdecoding of data in a certain block by the decoder 112 has beencompleted and a time at which writing of the decoded data in the blockconcerned into the decoded data memory 120 by the decoder 112 has beencompleted may be estimated on the high side and the format conversionunit 116 may decide a timing at which a predetermined time has elapsedafter reception of the progress signal PR as a timing at which the datain the block concerned becomes readable.

In addition, with regard to an address that the decoded data in theblock concerned has been stored in the decoded data memory 120, forexample, the progress notification unit 114 may output the number of theblock of the data whose decoding by the decoder 112 has been completedto the format conversion unit 116 as the progress signal PR, and theformat conversion unit 116 may acquire the address corresponding to thenumber of the block that the progress signal PR indicates in accordancewith a correspondence relation between the number of the block and theaddress in the decoded data memory 120.

In the above-mentioned case, the progress notification unit 114 may bereadily configured by a counter. Specifically, the counter may count upa value per picture, every time decoding of one-block data is completedby the decoder 112, or every time writing of the one-block decoded datainto the decoded data memory 120 is completed by the decoder 112, andmay output the counted value to the format conversion unit 116 as theprogress signal PR. Then, the counted value may be reset every timedecoding or writing of one-picture data is completed.

As mentioned above, in the present embodiment, the progress notificationunit 114 outputs the progress signal PR indicating the number of theblock concerned to the format conversion unit 116 per picture, everytime decoding of one-block data 112 or writing of the decoded dataperformed by the decoder 112 is completed. The format conversion unit116 is allowed to acquire information indicating the address that thedecoded data which has already been made readable from the decoded datamemory 120 is stored on the basis of the progress signal PR.

The format conversion unit 116 reads out the decoded data S2 from thedecoded data memory 120 and performs format-conversion on the data S2and writes the format-converted data into the format-converted datamemory 130 simultaneously with the decoding operation performed by thedecoder 112.

A read-out unit that the data is read out from the decoded data memory120 by the format conversion unit 116 either may be the same as or maynot be the same as a write unit that the data is written by the decoder112. From the viewpoint of efficiency of access to the memory, it ispreferable that the format conversion unit 116 be configured to performdata reading by defining a plurality of blocks as the read-out unit. Inorder to indicate that the read-out unit that the format conversion unit116 reads out the data may not to be the same as the write unit that thedecoder 112 writes the data, different symbols are respectively assignedin such a manner that S1 is assigned to the data (the decoded data) thatthe decoder 112 will write into the decoded data memory 120 and S2 isassigned to the data that the format conversion unit 116 will read outfrom the decoded data memory 120.

In addition, a write unit when the format conversion unit 116 will writeformat-converted data S3 into the format-converted data memory 130either may be the same as or may not be the same as a read-out unit whenthe format conversion unit 116 will read out the decoded data S2 fromthe decoded data memory 120.

The post-stage processing unit 140 reads out the data from theformat-converted data memory 130 or from the format-converted datamemory 130 and the decoded data memory 120 to perform processing inaccordance with the type of the processing to be executed.

According to the image processing device 100 of the present embodiment,first, it is allowed to simultaneously execute decoding of thecompressed image data by the decoder 112 and format-conversion of thedecoded data by the format conversion unit 116 by including both of thedecoded data memory 120 for storing the decoded data S2 and theformat-converted data memory 130 for storing the format-converted dataS3, and it is allowed not to put the decoder 112 on standby even whenexecution of format-conversion delays. Therefore, it is allowed topromote high-speed execution of the decoding and/or the processing ofthe entire system.

Further, the progress signal PR indicating the number of the latestblock decoding of data or writing of data in which has been completed isoutput from the progress notification unit 114 to the format conversionunit 116 per picture, every time decoding of one-block data or writingof one-block decoded data by the decoder 112 is completed. Thus, theformat conversion unit 116 is allowed to know the address that thedecoded data which has already been made readable from the decoded datamemory 120 is stored on the basis of the progress signal PR. That is, itis allowed to perform format-conversion on the decoded data in the blockdecoding of which has already been completed in the picture concernedeven when the decoder 112 does not yet complete decoding of one-picturedata. As a result, high-speed execution of format-conversion is allowed,and as a result of which it is allowed to perform the processing of theentire system at a higher speed.

Further, since the progress notification unit 114 simply notifies theformat conversion unit 116 of the state of progress that the data isbeing decided or written into the decoded data memory 120 by the decoder112 as control to be executed in order to obtain the above-mentionedadvantages, the control is simple.

Here, an operational example of the pre-stage processing unit 110 in theimage processing device 100 will be described in detail assuming thatthe format of the data (the decoded data) that the decoder 112 outputsis 2planar and the format of the data (the format-converted data) thatthe format conversion unit 116 outputs is 3planar.

FIG. 2 illustrates examples of one-picture decoded data having theformat of 2planar and one-picture format-converted data having theformat of 3planar. In FIG. 2, “Y” denotes a luminance pixel value, “U”and “V” denote a color difference U pixel value and a color difference Vpixel value respectively. In addition, a numeral coming after each of Y,U and V indicates a sequence of the pixel concerned.

As illustrated in FIG. 2, the decoded data includes two color planes ofone luminance (Y) plane and one color difference (UV) plane. The picturesize is W by H in width by height for the Y plane and is W by H/2 inwidth by height for the UV plane. As apparent from FIG. 2, in the UVplane of the decoded data, the U pixels and the V pixels are alternatelyarrayed.

On the other hand, the format-converted data includes one Y plane andtwo color difference planes (one U plane and one V plane). The picturesize is W by H in width by height for the Y plane and is W/2 by H/2 inwidth by height for each of the U and V planes.

That is, the format-conversion in this example is processing ofseparating the UV plane in the decoded data illustrated on the left sidein FIG. 2 into the U plane and the V plane illustrated on the right sidein FIG. 2. Incidentally, with regard to the UV plane, if there exist thedecoded data of two pixels in total of one U pixel and one V pixel,format-conversion will be allowed. Therefore, a minimum conversion unitof format-conversion is two pixels.

An example of an operation of the decoder 112 will be described withreference to FIG. 3. In FIG. 3, a small square in each color planeindicates a block, and a numeral in each block indicates a decodingorder that the data in the block concerned is decoded and a writingorder that the data in the block concerned is written into the decodeddata memory 120. In addition, one arrow indicates one decoding andwriting operation.

As illustrated in FIG. 3, the decoder 112 performs decoding of the dataand writing of the decoded data in units of blocks in order going fromleft to right and from up to down for each picture. For example, in acase where the size of one block is defined to be 16 pixels×16 pixels,when decoding of one-block data is completed, the decoded data of 16pixel×16 pixels for the Y plane and 16 pixels×8 pixels (the U pixels:8×8, and the V pixels: 8×8) for the UV plane are written into thedecoded data memory 120.

An example of an operation of the format conversion unit 116 will bedescribed with reference to FIG. 4. In FIG. 4, one arrow indicates oneoperation of reading the data from the decoded data memory 120 by theformat conversion unit 116.

In the example illustrated in FIG. 4, the format conversion unit 116 isconfigured to read out the format-converted data of one line in fourblocks in one reading operation. For example, in a case where theprogress signal PR from the progress notification unit 114 indicatesthat decoding of the data in the fourth block (the block 3) by thedecoder 112 has been completed, the format conversion unit 116, first,reads out the data of the first line from the first block (the block 0)up to the fourth block of the Y plane and the UV plane from the decodeddata memory 120 and perform format-conversion on the read-out data.After completion of format-conversion performed on these pieces of thedecoded data, the format conversion unit 116 writes the format-converteddata into the format-converted data memory 130, and reads out the dataof the second line from the first block up to the fourth block of the Yplane and the UV plane and performs format-conversion on the read-outdata simultaneously.

In the above-mentioned example, the block size is fixed throughout allthe pictures. The image processing device 100 according to the presentembodiment is allowed to cope with a situation that the block size ismade variable as in the standards such as HEVC and the forth.

Operational examples of the decoder 112 and the format conversion unit116 in a case where the block size is made variable in one picture willbe described with reference to FIG. 5 and FIG. 6.

First, with reference to FIG. 5, the operation of the decoder 112 willbe described. As illustrated in FIG. 5, in case of this example, thedecoder 112 decodes the data and writes the decoded data into thedecoded data memory 120 in order of the blocks 0, 1, 2, 3, 4, . . . withregard to each picture. In this case, the height and the width of eachof the blocks 1, 2, 3 and 4 are half the height and the width of theblock 0.

The operation of the format conversion unit 116 will be described withreference to FIG. 6. As illustrated in FIG. 6, for example, when theprogress signal PR from the progress notification unit 114 indicatesthat decoding of the data in the fourth block (the block 3) by thedecoder 112 has been completed, the format conversion unit 116, first,reads out the data of the first line in the respective blocks from thefirst block (the block 0) up to the third block (the block 2) of the Yplane and the UV plane and performs format-conversion on the read-outdata. After completion of format-conversion performed on these pieces ofthe decoded data, the format conversion unit 116 writes theformat-converted data into the format-converted data memory 130, andreads out the data of the second line in the respective blocks from thefirst block up to the third block of the Y plane and the UV plane andperforms format-conversion on the read-out data simultaneously.

Then, after completion of reading-out and format-conversion of thedecoded data in the block 1 and the block 2, the format conversion unit116 reads out the decoded data of the line which is the same as thefirst line in the block 3 in the block 0, and the data of the first linein the block 3 from the decoded data memory 120 and performsformat-conversion on the read-out data.

The image processing device 100 is applicable to the situation that theblock size which would be a unit for decoding is made variable and thesame advantage as that when the block size is fixed is obtained.

Incidentally, although in the present embodiment, the progressnotification unit 114 outputs the progress signal PR indicating thatdecoding of one-block data by the decoder 112 has been completed to theformat conversion unit 116 per picture by way of example, the progresssignal PR may be output to the format conversion unit 116 in units ofthe plurality of blocks upon completion of decoding of the data in thelast block of the plurality of blocks.

Further, the progress notification unit 114 may output the progresssignal PR indicating that decoding of the data of the entire pictureconcerned has been completed to the format conversion unit 116 perpicture. An example of this case will be described using a secondembodiment.

Second Embodiment

FIG. 7 illustrates an example of an image processing device 200according to a second embodiment. The image processing device 200 isdifferent from the image processing device in that a pre-stageprocessing unit 210 is included in place of the pre-stage processingunit 110, and the progress signal PR is output by a CPU 250.

The pre-stage processing unit 210 includes the decoder 112, a formatconversion unit 216 and the DMAC 118, and also includes the progressnotification unit 114 that the pre-stage processing unit 110 of theimage processing device 100 includes.

In an image processing device of this type, the decoder is generallyconfigured to output a signal indicating that decoding of one-picturedata has been completed to the CPU. The CPU controls the entire of theimage processing device in accordance with the above-mentioned signal.The decoder 112 in the image processing device 200 also outputs apicture decoding completion signal PD to the CPU 250 every time decodingof one-picture data is completed.

The CPU 250 has a function of outputting the progress signal PR to theformat conversion unit 216 upon reception of the picture decodingcompletion signal PD, in addition to general control processing. Thisfunction is performed by an illustrated progress notification unit 254.The progress signal PR is a signal indicating that decoding of the dataof the picture concerned has been completed and includes, for example,the number of the picture concerned.

Since the format conversion unit 216 recognizes that it is allowed toread out the decoded data from addresses ranging from an address (a baseaddress) corresponding to the first pixel of the picture concerned to anaddress corresponding to the last pixel of the picture concerned whenthe progress signal PR is received, it sequentially reads out thedecoded data of the picture concerned from the decoded data memory 120and performs format-conversion on the read-out data.

Although there are cases when delay occurs more frequently than in theimage processing device 100 because when decoding of one-picture data isnot completed, the image processing device 200 according to the secondembodiment is not allowed to start format-conversion of the data in theblock decoding of which has already been completed in the picture, it isthe same as the image processing device 100 in that it is allowed toexecute image processing including decoding and format-conversion at ahigh speed by simple control.

Although the invention which has been made by the inventors of thepresent patent application has been specifically described on the basisof the preferred embodiments thereof, it goes without saying that thepresent invention is not limited to the embodiments which have beenalready described and may be modified in a variety of ways within ascope not departing from the gist of the invention.

For example, although in each of the above-mentioned embodiments, theprogress notification unit outputs the number of the block concerned tothe format conversion unit as the progress signal PR, a signalindicating an address that the decoded data in this block has beenwritten into the decoded data memory may be output to the formatconversion unit as the progress signal. Also in this case, it is allowedto obtain the advantage brought about by the present invention.

In addition, although, for example, in each of the above-mentionedembodiments, the decoded data memory and the format-converted datamemory are separately illustrated, the decoded data memory and theformat-converted data memory may be different regions in one memory.

In addition, although, for example, in each of the above-mentionedembodiments, the DMAC is utilized to efficiently gain access to thememory, access to the memory is not necessarily gained via the DMAC.

In addition, although in the image processing device 100 according tothe first embodiment, the progress notification unit 114 is installedseparately from the decoder 112 and the format conversion unit 116, theprogress notification unit 114 may be built into either the decoder 112or the format conversion unit 116. In this case, it is preferable tobuild the progress notification unit 114 into the decoder 112 for readygrasping of the progress of encoding by the decoder 112 and readywiring.

In addition, in a case where the decoder 112 already has a signal whichis equivalent to the progress signal PR that the progress notificationunit 114 generates, it is not required to install the progressnotification unit 114 separately from the decoder 112, and the decodermay commonly function as the progress notification unit 114.

In addition, in the second embodiment, the progress notification unit254 in the CPU 250 outputs the number of the picture concerned as theprogress signal PR. Alternatively, the progress notification unit 254may generate and output a signal indicating an address that the decodeddata of the picture concerned is stored in the decoded data memory 120as the progress signal PR.

What is claimed is:
 1. An image processing device, comprising: a decodeddata memory for storing decoded data obtained by decoding compressedimage data; a format-converted data memory for storing format-converteddata obtained by performing format conversion on the decoded data; adecoder for decoding the compressed image data in units of blocks, andwriting the decoded data in the blocks into the decoded data memory; aprogress notification unit for generating and outputting a progresssignal indicating a state of progress of decoding or a state of progressof writing into the decoded data memory which is being executed by thedecoder per picture, and a format conversion unit for reading out thedecoded data from the decoded data memory and performing the formatconversion on the decoded data, and writing the format-converted datainto the format converted data memory, the format conversion unitadapted to acquire information indicating an address that the decodeddata which is readable from the decoded data memory is stored, from theprogress signal sent from the progress notification unit.
 2. The imageprocessing device according to claim 1, wherein the progressnotification unit generates and outputs a signal indicating the numberof the latest block decoding of the data or writing of the data into thedecoded data memory in which has been completed as the progress signalper picture, every time decoding of one-block data is completed by thedecoder or every time writing of one-block decoded data into the decodeddata memory is completed by the decoder.
 3. The image processing deviceaccording to claim 2, wherein the progress notification unit is acounter for counting up a value per picture, in accordance withcompletion of decoding of the one-block data or completion of writing ofthe one-block data into the decoded data memory by the decoder, andoutputting the counted value as the progress signal.
 4. The imageprocessing device according to claim 2, wherein the progressnotification unit generates and outputs a signal indicating an addressthat the data in the latest block is written into the decoded datamemory as the progress signal in place of the number of the latestblock.
 5. The image processing device according to claim 1, wherein theprogress notification unit is included in either the decoder or theformat conversion unit.
 6. The image processing device according toclaim 1, wherein the progress notification unit generates and outputs asignal indicating the number of the latest picture decoding of the dataor writing of the data into the decoded data memory in which has beencompleted as the progress signal per picture, every time decoding of thedata in the picture is completed by the decoder, or every time writingof the decoded data in the picture into the decoded data memory iscompleted by the decoder.
 7. The image processing device according toclaim 6, wherein the progress notification unit is included in an CPU(Central Processing Unit).
 8. The image processing device according toclaim 6, wherein the progress notification unit generates and outputs asignal indicating an address that the data in the latest picture hasbeen written into the decoded data memory, in place of the number of thelatest picture.